Once a year for only a few hundred miles is probably not necessary as long as it's not started every day. It's really the number of cold starts without driving it long enough to get the oil to temperature that causes acid formation which depletes TBN.
It's only a $20 oil change. While you could have the oil tested to optimize change intervals, the testing I use is $35 a pop, so the economics aren't there for you. My oil changes cost $100. By safely increasing my interval from 5,000 to 12,500 miles, I save $150 every 12,500 miles driven. That's significant. Saving $20 for every 300 miles is a greater cost per mile, however. Which is what you'd save by going to biannual changes.
I consider oil to be a "precious liquid" to the extent that it costs me money. The most "precious" oil I use is the synthetic stuff Bombardier says my two-stroke Rotax boat engine needs. That stuff runs nearly $60 per gallon, and the engine uses it only once. I have not been able to calculate it precisely, because usage is dependent on throttle opening, but I figure it adds well over a dollar an hour to the cost of running the boat.
Most service outfits around here "recycle" their used oil. One I know of burns it in the furnace used to heat their shop. I am told that is the fate of most recycled oil, and to the extent it replaces new oil in heating use it is recycled. Before the new requirements for cleaner diesel fuel, some trucking outfits used to run their used engine oil through a centrifuge and filter, then mix it at about 5% with fuel oil. It would not surprise to learn that used motor oil gets burned in ships, too. A local museum used to have an operational steam-powered train. They went to local service stations and collected used oil, then burned it in their locomotive.
The school for which I sometimes drive has several vehicles used for transporting students, including five buses, three or four vans, and a Suburban. Regulations require that each of those vehicles be inspected every 80 calendar days during the school year. Our maintenance guys change the oil at each of those required intervals, and don't worry about mileage.
I think thats the biggest problem, like fuel, oil is just far too cheap and readily available in the US. When a material is cheap, it just encourages people to use more, and/or waste it. An oil change here costs about $150 to $250 depending where you go.
I suppose the same can be said about food in the US food its very cheap, no doubt cheap fuel has a part to play in that too, so food is consumed in huge amounts/portions.
I cannot verify it, but I was told once on another forum that lubricating oil is almost a byproduct of refining petroleum for fuel. Most of the cost goes into additives, transportation, and packaging with the base oil being almost free. The small containers (quarts, liters) at the consumer level are a good part of the cost, and it will be noted that those containers are almost universally plastic, itself made from oil.
By the way, we here in the USA do not consider either oil or fuel to be "far too cheap." Others in the world may think so, but they have only to look at their Government tax policies to see why their petroleum is so expensive.
Not all of it's tax of course, the only reason you think fuel/oil isn't cheap there is because it's been cheap for so long, you've probably started taking it for granted. I guess it's all relative to average earnings, but if you take Turkey for example, they spend 36% of their wage on fuel. That's the same as the average American spending $15,000 on fuel, and they don't, the average American uses just $900 worth of fuel per annum. So if you ask me, you guys have it easy
$900 worth of fuel per year? I think that's absurdly low. Maybe if they're driving a Prius 12,000 miles/yr they might get away that cheap, but currently the average American drives about 15,000 miles/yr. On my Escape I drove 12,703 miles over the past 12 months, and spent $1,327 in fuel. If my Escape wasn't a hybrid, I'd get at least 10 MPG less, which would be even more fuel. I'd say a closer estimate would be $1,500 - $2,000/yr
I did say "average" im not sure what average is, average car, average miles im sure they are very different things in the US to the UK. The "average" UK driver spends $3600 on fuel compared to the $990 the "average" driver in the US spends.
There's probably a misinterpretation of data there. I would agree that if the "average" UK driver paid the equivalent US prices for fuel, they would pay about $900, but I believe the average US driver probably drives a lot more than the average UK driver. The average US vehicle also gets poorer fuel economy than the average UK vehicle, as US vehicles are generally larger vehicles.